1. Field of the Invention
This invention relates to a system for controlling the heating of buildings, and more particularly to maintaining an economical, steady comfort level in the perimeter zone or that interior space adjacent the building's outer walls. Further, the system is especially adapted to hot water heating.
2. Background of the Prior Art
In the past, numerous systems have been suggested for controlling the heating of buildings. The most common system is the ordinary thermostatic control in which a bimetallic strip remote from the room heat source, (usually mounted on an interior wall near the center of the building) operates a switch at predetermined levels to turn the heat inlet ON and OFF.
It has been found, especially in commercial buildings, that ordinary thermostatic control is undesirable. As a consequence numerous features have been added to promote fuel efficiency and increase comfort, among which are compensation for solar radiation, night temperature setback and automatic morning warmup. The latter features have been particularly stressed because of new requirements arising from the BOCA Code.
Recently, the present inventor disclosed a unique system for electrical heating control which is the subject of U.S. Pat. No. 4,582,982, issued Apr. 15, 1986 and which is marketed as the PACE.RTM. system by General Electronic Engineering, Inc., of Rahway, N.J., assignee of the aforesaid patent. While the system has gained acceptance, a long felt need for adaptation to hot water went unfulfilled as a control system meeting the special requirements of hot water heating and the PACE system was unavailable. As will be found by reading the description of the invention which follows, these needs are met by a new and novel system that is both highly responsive and economical.
In the course of preparation for the instant application a patentability search was performed having a field of search which included U.S. Classifications 236/lB and 364/557. The search uncovered the following patents:
______________________________________ U.S. Pat. No. Inventor Date of Issue ______________________________________ From Class 364/57 4,661,914 William Mulokey et al. April 28, 1987 4,555,764 Thomas Kuehn Nov. 26, 1985 4,527,246 Vijay Masson July 2, 1985 4,483,152 James M. Bitondo Nov. 20, 1984 4,475,685 Phillip B. Grimado et al. Oct. 9, 1984 4,455,095 Werner Bleiker June 19, 1984 4,390,959 Christian G. Cabou June 28, 1983 4,332,013 Darrell Chelcun, et al. May 25, 1982 4,136,392 Bruce D. Westphal et al. Jan. 23, 1979 4,034,801 William F. Berstein From Class 236/1B 4,718,021 Stanley W. Timblin Jan. 5, 1988 4,393,662 George Dirth July 19, 1983 3,567,115 Lorne W. Nelson Dec. 7, 1970 2,701,128 L. H. Gilleck et al. Feb. 1, 1955 2,292,160 E. W. Roessler Aug. 4, 1941 ______________________________________
Of the patents included on the search, many of the patents had exterior sensors to monitor outdoor temperature, but none of them seemed to rely upon such sensors and building characteristics for controlling perimeter heating. Additionally, the control systems described in the patents uncovered on the search, do not teach toward utilization thereof as a reference in combination with U.S. Pat. No. 4,582,982 to be applied against a hot water PACE system.
Of the patents uncovered, Grimado et al., U.S. Pat. No. 4,475,685 (hereinafter Grimado '685) monitors outside temperature and controls the heating system by a device which determines a time interval of thermal energy addition which is required to achieve a predetermined temperature. Likewise Westphal et al., U.S. Pat. No. 4,136,391, (hereinafter Westphal '391), correlates data from an outside temperature sensor with a look-up table which provides for cycling loads on and off, according to a predetermined cycle rate.